Journal of Reproduction and Development
Online ISSN : 1348-4400
Print ISSN : 0916-8818
ISSN-L : 0916-8818
Volume 44, Issue 4
November
Displaying 1-14 of 14 articles from this issue
Review
  • Naganari OHKURA, Kouji MARUYAMA, Toshihiko TSUKADA, Tetsuji HOSONO, Ke ...
    1998 Volume 44 Issue 4 Pages 321-335
    Published: 1998
    Released on J-STAGE: October 31, 2001
    JOURNAL FREE ACCESS
    The steroid/thyroid receptor superfamily comprises a group of structurally related transcription factors that program developmental, physiological, and behavioral responses to a variety of signals. NGFI-B, Nurr1 and NOR-1 are members of this superfamily of ligand-inducible transcription factors, and constitute one subgroup called the NGFI-B family. However, ligands have not yet been identified for the family members, and therefore they also belong to the category of “orphan receptors.” Although our knowledge of the NGFI-B family is limited, it is clear that these transcription factors have important functions in mediating responses to various signals and play critical roles in biological processes including cell growth, differentiation and apoptosis. In this review, we summarize their structural features, genomic organization, gene expression and transcriptional regulation, and illustrate their biological functions inferred from recent reports.
    Download PDF (395K)
Original Articles
  • Fumihiko MAEKAWA, Korehito YAMANOUCHI
    1998 Volume 44 Issue 4 Pages 337-343
    Published: 1998
    Released on J-STAGE: October 31, 2001
    JOURNAL FREE ACCESS
    The role of the dorsal raphe nucleus in the maintenance of pseudopregnancy induced by reserpine and/or vaginal stimulation was investigated in female rats. In order to induce pseudopregnancy, either the vagina was stimulated electrically (VS) on the day of proestrus, or 1 mg/kg b.w. reserpine (R) was injected on the day of diestrus I. In some females, both VS and R treatments (VS+R) were applied. Radiofrequency lesions were made in the dorsal raphe nucleus (DRL) 5 days after VS and 3 days after R. At the same time, the left uterine horn was traumatized in order to induce deciduoma. As a result, positive decidual responses were seen in most control and sham-control rats with VS or R-treatments. In contrast, the incidence of deciduoma in DRL females with R injection was lower than that in control and sham groups, but the incidence in DRL females with VS or VS+R was comparable to that in control and sham females. These results suggest that the dorsal raphe nucleus plays an important role in maintaining the mechanism of pseudopregnancy induced by reserpine, but not in that induced by vaginal stimulation.
    Download PDF (125K)
  • Hiroyuki SUZUKI, Jyh-Cherng JU, Jhon E. PARKS, Xiangzhong YANG
    1998 Volume 44 Issue 4 Pages 345-351
    Published: 1998
    Released on J-STAGE: October 31, 2001
    JOURNAL FREE ACCESS
    Surface morphology of the zona pellucida (ZP) and the vitellus of bovine oocytes treated by heat shock were evaluated by scanning electron microscopy (SEM). Bovine oocytes were recovered from slaughterhouse ovaries and matured in vitro for 24 h (young oocytes) or 40 h (aged oocytes). After maturation incubation, they were heat-shocked at 42 C for 30 min and then incubated at 39 C for 1, 2, 4, 8 and 16 h. The ZP was characterized by a mesh-like structure in untreated young oocytes, whereas in untreated aged oocytes the ZP meshwork became thinner. After heat shock, partial breakage (16/69) or coalescence (53/69) of the ZP meshwork was noted in young oocytes, and the altered surface of the ZP was not restored during incubations for up to 16 h. In aged oocytes, however, partial peeling off of the outer ZP surface was noted frequently after heat shock (6/10 at 1 h, 10/10 at 2 h, 7/10 at 4 h and 6/6 at 8 h). The vitelline surface of untreated young oocytes was predominantly covered by well-developed microvilli (MV). In aged oocytes, a mixed distribution pattern of MV and cytoplasmic protrusions (CP) was frequently noted (8/9). After heat shock, the observance of the mixed MV and CP increased in the young and aged oocytes and enlarged CP were observed more frequently in the aged oocytes. These observations suggest that a brief heat shock (42 C, 30 min) facilitates a breakage of the ZP surface and changes the vitelline surface from a MV-predominant to a CP-predominant pattern; furthermore its effect may manifest itself more quickly and to a greater degree in aged oocytes than in the young oocytes.
    Download PDF (223K)
  • Amanda L. TREWIN, Charles L. CHAFFIN, Gen WATANABE, Kazuyoshi TAYA, Re ...
    1998 Volume 44 Issue 4 Pages 353-357
    Published: 1998
    Released on J-STAGE: October 31, 2001
    JOURNAL FREE ACCESS
    We proposed to describe the cyclic changes in serum follicle-stimulating hormone (FSH), luteinizing hormone (LH) and inhibin during the guinea pig estrous cycle. Serum gonadotropin concentrations had not been determined routinely because antibodies to guinea pig gonadotropins were rarely available. Serum gonadotropin concentrations provide important information about the stimuli received by the ovary. Inhibin plays a major role in modulating FSH synthesis and secretion at the anterior pituitary; and inhibin concentrations can be used as a marker for follicular development. We used only sexually mature guinea pigs that showed at least two consecutive normal 15-17 day cycles. The day of maximal vaginal cornification, the day of ovulation, was designated as day 0. Blood samples were taken every other day at 0900 hours throughout one estrous cycle. Serum was analyzed for FSH, LH, and inhibin by radioimmunoassay. Cyclic changes in peripheral FSH, LH, and inhibin concentrations were observed. Serum inhibin rose to a peak on day 7 of the guinea pig estrous cycle. Inhibin increased again, although not significantly, on day 13. Thus, this study confirms the biphasic phenomenon of ovarian follicle development in guinea pigs. Since serum FSH concentrations declined as serum inhibin concentrations reached a peak, it is also suggested that inhibin regulates FSH secretion in this species. This is the first study in which all three hormones were measured during the estrous cycle of the guinea pig.
    Download PDF (93K)
  • Nao ARAKI, Katsuhiro SATO, Kanako HAYASHI, Akio MIYAMOTO, Yutaka FUKUI
    1998 Volume 44 Issue 4 Pages 359-365
    Published: 1998
    Released on J-STAGE: October 31, 2001
    JOURNAL FREE ACCESS
    The effects of follicular fluid estradiol-17β (FFE) concentration of individual follicle and the morphology of cumulus-oocyte complexes (COCs) on in vitro development of in vitro matured (IVM), in vitro fertilized (IVF) and in vitro cultured (IVC) bovine oocytes were investigated. All COCs were cultured individually throughout IVM to IVC. The types of cumulus cell layer were ≥4 and 2-3 layers, and the ooplasm types were homogeneous and heterogeneous (granulation). FFE in each follicle sized 2-8 mm in diameter was measured individually by enzyme immunoassay. Mean FFE concentration in the follicles containing oocytes with heterogeneous ooplasm was significantly lower (P<0.05) than that in follicles giving oocytes with homogeneous ooplasm (921 vs. 1493 pg/ml). The types of cumulus cell layer did not show significant difference in levels of FFE. However, regardless of the ooplasm types, developmental capacity was significantly higher (P<0.05) in the oocyte with ≥4 layers of cumulus cells than the oocytes with 2-3 layers of cumulus cells. The oocytes aspirated from follicles with less than 100 pg/ml FFE resulted in significantly low (P<0.05) proportions of cleavage, blastocyst and hatched blastocyst development as compared with those aspirated from follicles with higher FFE. The present results indicate that FFE levels affect oocyte quality and the in vitro developmental capacity of bovine oocytes cultured individually throughout IVM to IVC.
    Download PDF (132K)
  • Noris ROA, Tiburcio LINARES, Morella R. de ROLO, Rita TAMASAUKAS
    1998 Volume 44 Issue 4 Pages 367-370
    Published: 1998
    Released on J-STAGE: October 31, 2001
    JOURNAL FREE ACCESS
    Plasma Progesterone (P4) concentrations were determined by Enzyme-Linked Immuno absorbent Assay (ELISA) in 47 crossbred recipients (Bos indicus x Bos taurus) in a commercial embryo transfer (ET) program in the savannas of Venezuela. This study was carried out to evaluate the reproductive response of these embryo recipient heifers. Pregnancy status was confirmed by rectal palpation 60 days after estrus. Pregnancy rates were 38.3% (18/47) while a 61.7% stayed open. There were no significant differences between plasma P4 concentration of females that remained pregnant and those that did not either on day 0 (estrus) or 7 (ET). On day 21, the mean concentrations of P4 in pregnant females was 12.2 ng/ml being significantly higher compared to non-pregnant females (0.82 ng/ml). Recipients having plasma P4 concentrations of 2 ng/ml or more on day 21 were considered pregnant. This type of early pregnancy diagnosis using as a discrimination criterion 2 ng/ml of P4 in plasma, had an efficiency of 75% in detecting pregnant recipients and 100% in detecting open heifers correctly, for day 21 post estrus. It was concluded that this type of heifers has a good reproductive response as recipients of embryos in the Venezuelan tropics. Evaluating the concentrations of P4 on day 21 after estrus gave a high percentage of certainty in the early diagnosis of pregnancy. This would allow us to reuse the open recipient for ET before 60 days post estrus, and reduce the cost for maintenance.
    Download PDF (81K)
  • Hiroshi NAGASAWA, Yoshie IKEZAKI, Kazutoshi YAMAMOTO
    1998 Volume 44 Issue 4 Pages 371-375
    Published: 1998
    Released on J-STAGE: October 31, 2001
    JOURNAL FREE ACCESS
    To understand the relationship between transforming growth factor α (TGFα) and mammary gland involution, changes in the growth of normal and preneoplastic mammary glands, the expression of TGFα and epidermal growth factor receptor (EGFR) mRNAs in the mammary gland, and serum prolactin (PRL) level were examined in 3-month-old virgin SHN mice 4 to 108 days after ovariectomy (OVX). The formation of normal end-buds and preneoplastic hyperplastic alveolar nodules was significantly reduced after 9 days of OVX, associated with the decreased serum PRL level. Both TGFα and EGFR mRNA expression in the mammary glands declined 18 days after OVX. Thereafter, TGFα mRNA tended to increase, while EGFR mRNA continued to decrease. These observations suggest that the decline of both estrogen and PRL play major roles in the mammary gland involution after OVX, and that the decline of EGFR, through which TGFα manifests its effects, play a secondary role in this process.
    Download PDF (104K)
  • Eiichi HONDO, Hiroshi MURABAYASHI, Hiroshi HOSHIBA, Nobuo KITAMURA, Ke ...
    1998 Volume 44 Issue 4 Pages 377-383
    Published: 1998
    Released on J-STAGE: October 31, 2001
    JOURNAL FREE ACCESS
    Developmental changes of horse testis were examined morphologically. Spermatogenesis initiated in the spring of 2-year-olds, and spermatogenic activity appeared to increase age dependently up to 9 years old. The characteristic feature of fetal testis is its large interstitial mass. The interstitial region revealed no proportionate change during the fetal period, but gradually decreased with age-dependency from birth to 9 years old. On the other hand, the area of seminiferous tubules showed no changes up to 1 year old. Most characteristic feature during development is the appearance/disappearance of pigmented cells. These cells first appeared in 3-day-old individuals and gradually increased in volume up to 1 year old (sampled in spring). The number of cells reached maximum at 2 months old, gradually decreased, and completely disappeared after 3 years old. The pigmented cells possessed large and small round bodies with various electron densities in the cytoplasm.
    Download PDF (370K)
  • Akio MIYAMOTO, Takeshi NAKATSUKA, Masayuki OHTANI, Yutaka FUKUI
    1998 Volume 44 Issue 4 Pages 385-391
    Published: 1998
    Released on J-STAGE: October 31, 2001
    JOURNAL FREE ACCESS
    The role of tumor necrosis factor-α (TNF-α) in the local regulatory mechanisms of functional luteolysis in the ewe was examined. TNF-α was infused into a microdialysis system (MDS) implanted in the corpus luteum (CL) for 24 h from 2 h after the intramuscular injection of cloprostenol (defined as 0 h), and plasma as well as intraluteal changes of progesterone (P) and prostaglandins (PG) were observed. Three ewes were treated for superovulation, and multiple CL formed thereafter were surgically implanted with the MDS (1 line/CL) on Day 7 after GnRH injection. Serial fractions from the MDS were collected every 30 min for 40 h on Days 9-11 following a pre-perfusion period of 30 h. An intramuscular injection of cloprostenol stimulated an acute increase of plasma P concentration (an increase to 150%) within 1 h, followed by a rapid decrease within 6 h (P<0.05), which directly correlates with functional luteolysis. Intraluteal P release into the MDS showed a profile similar to that in the plasma, but significantly decreased from 17 h (P<0.05). Twenty-four-hour infusions of TNF-α at 20 ng/ml and 200 ng/ml into the MDS starting at 2 h after cloprostenol injection slightly hastened the time of onset of P decrease when they were compared with the time of the control. In contrast, the higher dose of TNF-α at 2000 ng/ml clearly delayed the time of onset of P decrease. Intraluteal release of PGF and PGE2 in the control was slightly increased between 18-32 h (P<0.05). A 26-h infusion with indomethacin partly blocked the increase in basal release of both PG (P<0.05), whereas it had no effect on the P release. A 24-h infusion with different concentrations of TNF-α stimulated the release of PGE2, but not the release of PGF (P<0.05). The results support the idea that TNF-α may have a passive or secondary role in functional luteolysis. Furthermore, the intraluteal PG production appears to have no direct correlation with functional luteolysis.
    Download PDF (129K)
  • Kaoru YAMASHITA SUZUKI, Korehito YAMANOUCHI
    1998 Volume 44 Issue 4 Pages 393-398
    Published: 1998
    Released on J-STAGE: October 31, 2001
    JOURNAL FREE ACCESS
    In order to clarify the role of the medial forebrain bundle (MFB) in regulating female sexual behavior in male rats, lordosis and soliciting behavior were observed after transection of it. Male rats were castrated and received cutting of the bilateral MFB at the suprachiasmatic level or sham operation. As control groups, male and female rats were castrated without brain surgery. Behavioral test was carried out after implantation of Silastic tubes containing estradiol. As a result, all males with MFB cuts showed lordosis behavior. Lordosis quotient in this group was comparable to that of female control and was higher than those in the control male and sham male rats. Half male rats with MFB cuts but none of control and of sham males showed soliciting behavior. These results suggest that the MFB is an important inhibitory pathway for female sexual behavior in male rats.
    Download PDF (118K)
  • Shinji TSUKAHARA, Hiroko TSUKAMURA, Kei-Ichiro MAEDA
    1998 Volume 44 Issue 4 Pages 399-405
    Published: 1998
    Released on J-STAGE: October 31, 2001
    JOURNAL FREE ACCESS
    The present study aimed to determine whether nitric oxide (NO) mediates the effect of glutamate on gonadotropin-releasing hormone (GnRH) release from the arcuate nucleus-median eminence, and whether estrogen modulates the NO action. Arcuate nucleus-median eminence fragments taken from ovariectomized (OVX) or estradiol-primed OVX rats were incubated in a medium containing glutamate with or without NGmonomethyl-L-arginine (NMMA), an nitric oxide synthase inhibitor, or hemoglobin (Hb), an NO scavenger. Cyclic guanosine 3', 5'-monophosphate (cGMP) levels in tissue fragments were also measured. Glutamate induced GnRH release in the estradiol-primed OVX group. The glutamate-induced GnRH release was reduced by NMMA or Hb without a significant change in cGMP levels. In the OVX group, glutamate did not increase GnRH release, but the release was stimulated by combination with NMMA or Hb. The cGMP level was increased by glutamate and this increase was reduced by Hb or NMMA. These results suggest that NO has both stimulatory and inhibitory effects on glutamate-induced GnRH release from the arcuate nucleus-median eminence fragments, and that estrogen alters the NO actions to modulate the glutamate-induced GnRH release.
    Download PDF (132K)
  • Yutaka FUKUI, Midori OKADA, Naohisa ISHIDA
    1998 Volume 44 Issue 4 Pages 407-412
    Published: 1998
    Released on J-STAGE: October 31, 2001
    JOURNAL FREE ACCESS
    The incidence of premature corpora lutea (CL) regression was investigated in three different breeds (Merino × polled Dorset: MD, Suffolk: S, and South-Down: SD), parous and non-parous ewes (a total of 46 ewes) treated for superovulation during and out of the breeding season. Superovulation was induced with a single injection of 20 mg porcine follicle-stimulating hormone (pFSH) 2 days and 500 IU equine chorionic gonadotropin (eCG) 1 day, respectively before the removal of synthetic progestogen (40 mg FGA) vaginal sponges inserted for 12 days. All ewes were inseminated into the uterus with fresh-diluted or frozen-thawed semen by laparoscope, and a number of newly formed and regressed CL were recorded. Breed difference significantly (P<0.005) affected the incidence of premature regressed CL; S (6.3%, n=16) ewes were less in the proportion of the incidence of regressed CL than MD (37.5%, n=16: P<0.05) and SD (71.4%, N=14, P<0.01) ewes. The use of non-parous ewes and treatment during autumn tended to result in higher rates of incidence of premature CL regression than the use of parous ewes and treatment during spring. These results indicate that the incidene of premature CL regression in superovulated ewes was influenced by not only season and parity but also by breed of ewes used for superovulation treatment.
    Download PDF (86K)
  • Masahiko NISHIGAI, Hideo KAMOMAE, Tomomi TANAKA, Yoshihiro KANEDA
    1998 Volume 44 Issue 4 Pages 413-419
    Published: 1998
    Released on J-STAGE: October 31, 2001
    JOURNAL FREE ACCESS
    Blood progesterone (P) concentrations were determined on the previous day (6 days after onset of estrus; day 6) and the day of embryo transfer (7 days after onset of estrus; day 7) in recipients of Japanese Black beef cow to clarify the correlation between luteal function and pregnancy rate in the stepwise transfer method of frozen Japanese Black embryos. When the blood P concentrations on both day 6 and day 7 in the bovine recipients increased, the pregnancy rate also tended to increase. Pregnancy rates in the recipients with blood P concentration <2.5 ng/ml and ≥2.5 ng/ml on day 6 were 38.6% (17/44) and 60.7% (34/56), respectively, showing a significant (P<0.05) difference. The pregnancy rate in the recipients with blood P concentration <2.5 ng/ml on day 7 was 35.7% (10/28), while the corresponding rate was 56.9% (41/72) in the recipients with blood P concentration of ≥2.5 ng/ml, showing no significant difference. The pregnancy rate in the recipients in which blood P concentration was <2.5 ng/ml on day 6, and increased to ≥2.5 ng/ml on day 7 was low at 45.0% (9/20), while the rate in the recipients which showed blood P concentration of ≥2.5 ng/ml on both day 6 and day 7 was as high as 61.5% (32/52). The relationship between the blood P concentration and luteal development on day 6 corresponding to pregnancy rate was investigated by dividing corpus luteum (CL) into the following three groups by rectal palpation findings : favorably developing, poorly developing and cystic groups. The mean blood P concentration was 2.8 ng/ml in the favorably developing CL, whereas the levels were as low as 2.0 ng/ml and 2.1 ng/ml in the poorly developing CL and cystic CL, respectively. The pregnancy rate for the favorably developing CL was 55.3% (42/76) which tended to be higher than for the poorly developing CL, (44.4% (8/18)), and cystic CL, (16.7% (1/6)), respectively. These observations showed that a high pregnancy rate is achieved by selecting cows with blood P concentration of ≥2.5 ng/ml on day 6 and day 7 of embryo transfer.
    Download PDF (95K)
Research Note
  • Masayuki KOBAYASHI, Ryuya HORIUCHI
    1998 Volume 44 Issue 4 Pages 421-425
    Published: 1998
    Released on J-STAGE: October 31, 2001
    JOURNAL FREE ACCESS
    The aim of this study was to examine the effects of two kinds of rat hepatoma cell-conditioned media (CM) on in vitro development of bovine embryos matured and fertilized in vitro under chemically defined conditions. Medium conditioned with Reuber H-35 or BRL 3A cells was prepared by a 24-h culture in the absence of both serum and bovine serum albumin (BSA). Two days after in vitro fertilization, bovine embryos were cultured in these conditioned media. After 2 days of culture in the control or in BRL CM, 15-18% of embryos were developed to the morula stage. Although a significant difference was not found, the developmental rate was increased to 22.4% when embryos were cultured in Reuber CM. Additionally, the percentage of degenerated embryos cultured with Reuber CM was significantly decreased (33.5%; p<0.01) compared to that of control embryos (49.4%). These results demonstrated the positive effects of serum- or BSA-free Reuber CM on the inhibition of early degeneration of bovine embryos matured and fertilized in vitro.
    Download PDF (85K)
feedback
Top